The table saws in David Butler's (left) workshop are outfitted with prototypes of his "Whirlwind" safety brake system. He and his lifelong friend Robert Calhoun filed their first Whirlwind Tool Co. patent in 2009.

David Butler designed his safety brakes so they could be easily installed on existing saws and machine tools. This prototype is installed on a Delta 15-inch scroll saw, a model that has been used for decades in schools.

Chris ArnoldNPR

When you think of cutting-edge technology, power tools don't generally come to mind. Take the table saw: Many woodworkers are using 30-year-old saws in their wood shops and, among the major tool companies, there hasn't been much innovation since those decades-old tools came out.

But more and more inventors are trying to make these saws safer — and David Butler is one of them. At his home in Cape Cod, Mass., Butler flips on the fluorescent lights in his basement turned wood shop.

"I've been a lifelong woodworker," Butler says. And he has a dozen different power saws — table saws, band saws, scroll saws — to prove it, each of which is fitted with various prototypes of his invention.

Butler has spent most of his professional career as an electrical engineer — woodworking is more of a hobby. At 18, he was a Navy electronics technician working on the Navy's first fighter jet. In 1958, he started working for IBM. He says the company paid for him to go to school for eight months and then "turned me loose on the world's largest computer, the SAGE air defense system." From there, Butler went on to work for General Electric, Citibank and other major companies. And now, here in his basement workshop, Butler has come up with an impressive invention: a safety brake for table saws.

4,000 Amputations A Year And Counting

NPR has done a series of stories on another company, SawStop, that also produces a high-tech table saw safety brake. But despite the 4,000 grisly table saw amputation injuries that happen every year in the U.S., the broader industry has resisted adopting such brakes.

Now, Butler is the latest inventor to show that these saws could be a lot safer.

Butler calls his system the Whirlwind. It uses a blade guard cover and a vacuum that sucks away sawdust while you cut wood. If you touch the blade guard while the saw is running, it sets off a sensor that triggers the safety brake. The blade stops spinning in less than a second, keeping the user from accidentally running his hand into it.

Butler's system works using something called electronic braking. Power saw motors — like electric lights, appliances and basically everything we plug into the wall at home — run on AC power. It's the electrical power standard in the U.S. But, according to Butler, if you cut that power in exactly the right way, it's "like pulling the plug out of the wall." And if you then hit it with a jolt of DC current, that's like slamming on the brakes — within a second, Butler says, "you can stop the motor."

Whirlwind Vs. SawStop

Both Whirlwind and SawStop have their advantages and disadvantages. According to Butler's business partner, Robert Calhoun, one thing that's nice about Whirlwind is "you don't have to go out and buy a brand new table saw." Whirlwind is designed to be retrofitted onto any existing saw. Butler says even the 40-year-old table saw in your grandfather's basement could be made much safer by outfitting it with a Whirlwind safety brake. Whirlwind also doesn't destroy the saw blade when stopping it, so you can just reset the brake and keep working.

But SawStop is faster — the brake kicks in within just a few one-thousandths of a second — and it also uses the saw blade itself as a sensor, so you don't need a guard covering the blade for the safety brake to work. Regulators and safety advocates say that's a distinct advantage because many woodworkers end up removing blade guards so they can work faster and more easily.

A Long Road To The Store Shelf

The biggest advantage, though, is that you can actually buy a SawStop saw. Whirlwind is still in the prototype stage and, unfortunately for woodworking enthusiasts, not being sold yet. That's because it's a long road from the drawing board to the store shelf, and so far the major power tool companies have resisted adopting this kind of advanced safety technology.

In fact, SawStop inventor Steve Gass had to start his own saw manufacturing company to bring his invention to market. But Butler says he isn't prepared to do that. He's looking to license his technology to another company to build and sell.

So far, none of the major power tool companies (including Delta, Ryobi, Black and Decker, Milwaukee and others) are even offering these types of advanced, so-called flesh-sensing safety brake systems on their saws. But that may change. The Consumer Product Safety Commission has begun drafting new table saw safety regulations — regulations that may very well require advanced systems like those invented by Whirlwind and SawStop.

Copyright 2013 NPR. To see more, visit http://www.npr.org/.

Transcript

AUDIE CORNISH, HOST:

From NPR News, this is ALL THINGS CONSIDERED. I'm Audie Cornish.

ROBERT SIEGEL, HOST:

I'm Robert Siegel. It's Monday, time for All Tech Considered.

(SOUNDBITE OF MUSIC)

SIEGEL: And we go retro in today's segment with a 21st century nod to some old technology. We'll start with an innovation that makes table saws safer. Tens of thousands of people are injured using table saws every year.

NPR's Chris Arnold visited an inventor who wants to change that.

CHRIS ARNOLD, BYLINE: At his home in Cape Cod, David Butler flips on the fluorescent lights in his finished basement.

DAVID BUTLER: We're in my home workshop. I've been a lifelong woodworker.

ARNOLD: There are a dozen different power saws down here, each with various prototypes of his invention bolted onto them.

BUTLER: And if you walk over here...

(SOUNDBITE OF FOOTSTEPS)

BUTLER: This saw,

ARNOLD: Woodworking is a hobby. For his career, Butler has been an electrical engineer. At the age of 18, he was a Navy electronics technician who worked on the Navy's first jet fighter. He then went on to work for IBM starting in 1958.

BUTLER: IBM paid me for eight months to go to school and turned me loose on the world's largest computer, the SAGE air defense system. And it went on and on. I worked for General Electric, for Citibank.

ARNOLD: And here in his basement workshop, Butler has come up with an impressive invention. It's a safety brake for a table saw. We've done stories about a different company called Sawstop, which has a high tech safety brake, too. The broader industry has resisted adapting it. That's despite 4,000 grisly amputation injuries every single year in the U.S. on table saws. Now, along comes David Butler.

BUTLER: Let me start it.

(SOUNDBITE OF TABLE SAW)

ARNOLD: Now we'll trigger the brake.

(SOUNDBITE OF BELL)

BUTLER: Boom.

ARNOLD: That was quick

BUTLER: That's quick.

ARNOLD: Butler calls his system the Whirlwind. That's because the system uses a blade guard cover that also has a vacuum that sucks away the sawdust while you cut the wood.

(SOUNDBITE OF TABLE SAW)

ARNOLD: If you touch the plastic guard covering the skinny saw blade that sets off a sensor. And then the brake kicks in.

BUTLER: I can trigger this without the saw even running. Watch.

(SOUNDBITE OF THUMP)

ARNOLD: What was that sound? Is there a compressor in there or something?

BUTLER: No, it's a sound of - it's electronic braking

ARNOLD: Saw motors run on what's called AC current. But Butler says if you cut that power and then send DC current into the motor in exactly the right way...

BUTLER: Like pulling the plug out of the wall and then hit it with a rapid big surge of DC, you can stop the motor.

ARNOLD: Compared to Sawstop, each system has advantages and disadvantages. But one thing that is nice about Whirlwind...

ROBERT CALHOUN: You don't have to go out and buy a brand new table saw.

ARNOLD: That's Butler's lifelong friend and business partner Robert Calhoun. He says that you can retrofit this brake onto any existing saw.

CALHOUN: So you can go out and your delta saw, which you have in the basement, which is 20 years old, we will have a kit.

ARNOLD: Unfortunately for woodworking enthusiasts out there, you can't buy this safety brake yet. And that's the problem for a lot of inventors. The drawing board to the store shelf is a long road. And the major power tool companies, in this case, so far are not embracing these new high tech safety innovations. When it comes to table saws though, that may change.

The Consumer Product Safety Commission has begun drafting new table saw safety regulations. And those may very well require advanced systems such as Whirlwind or Sawstop.